Manufacture of hollow metal balls.



PATENTEI) FEB. '7, 1905.

A. JOHNSTON. MANUFACTURE OF HOLLOW METAL BALLS.

APPLICATION TILED 1330.1;1003.

alto-mugs Patented February '7, 1905.

NTTEn STATES PATENT @rrice.

ALLEN JOHNSTON, OF t).l."l.Ui\lll'-\, lOlVA.

MANUFACTURE OF HOLLOW METAL BALLS- SPEOIFIGATION forming part of Letters Patent No. 781,951 dated February 7, 1905.

Application filed December 1,1903. Serial No. 188,385.

To all whom, [25 17M! coltccl-lt:

Be it known that l, ALLnxJouxs'rox, a resident of Ottumwa, lowa, have invented a new and useful Improvement in the Manufacture of Hollow Metal Balls, which invention is fully set forth in the following specilicatioi'i.

This invention relates to the manufacture of hollow metallic balls, particularly such as are made from sheet-metal blanks and adapted for use as bearing-balls.

The object is to assure the production of tightly-closed seams in the operation of forming the balls, and to that end the principal feature of the invention consists in forming a cup having a laterally and inwardly inclined edge or edges, whereby when said cup is closed the opposing portions of the edge or edges will be sure to make contact at the outer surface of the ball. seams is thus avoided, thereby greatly simplifying the subsequent finishing operations.

The process constituting the invention will be more readily understood by reference to the accompanying drawings, wherein Figure l is a sheet-metal blank. Fig. 2 is a cup formed from said blank. Fig i. a

plan view of a completed ball; and Fig. 4c is a sectional view on line i, Fig. 3. Fig. :3 shows a punch and die suitable for formingthe blank into a cup, and Fig. 6 shows dies suitable for closing the cup.

In proceeding according to my invention a sheet-metal blank of any suitable shape and thickness such, for example, as the square blank a, Fig. l is placed over the hole 2 in die 3, Fig. 5, the gage-plate 4, into which the blank fits, serving to accurately center the latter over the hole. Punch 5 is then caused to operate on the blank, transforming it into a cup I), Fig. 2, having an irregular or pointed edge e around its open end, said edge being, furthermore, laterally inclined in wardly,causing the outer surface of the cup to project beyond or to extend upwardly farther than its inner surface. The preferred way of producing the inward inclination is to employ a punch 5, the diameter of which is greater than the diameter of opening 2 minus twice the thickness of the blank. For example, in making balls one-quarter of an inch in diameter from The formation of gaping material .025 of an inch in thickness the desired results have been attained by making the diameter of the die-opening .238 of an inch and of punch 5, .198 of an inch, the difference between these diameters being .(Ml) of an inch, or .010 of an inch less than twice the thickness of blank 1/, which is .050. It follows that in the formation of a cup the punch and die will cooperate to draw out and reduce the thickness of the annular portion or wall of the formed cup which lies between the l punchandwallof thedie-opening. The punch and blank of course move together relatively to the die, and in entering and passing through the die-opening the blank must slide along the wall thereof. The result is that the drawing of the metal takes place largely at the outer surface of the cup, causing said outer surface to extend upwardly beyond its inner surface and giving a lateral inward inclination to the edge 1.. The bottom of the cup will be slightly thinner than the original blank, but thicker than the side wall, depending u pen the amount of drawing which takes place. in the example being described the cup thus formed and having a diameter of .238 is closed by dies 6 and T, the diameter of the dieopenings corresponding to that desired for the balls.25 of an inch. These dies in acting on the cup will swell or expand it from the diameter .238 (imparted by punch 5 and die 3) to .250 and force the points r/of the blank tightly together, forming scams 0. The formation of seams tightly closed at the outer surface of the ball is assured by the lateral inward inclination of the edge or edges (1.

Of course any desired form and dimensions of blank, dies, and punches may be used, those given above being merely illustrative. l urthermore, the cup having a lateral inwardlyincline 1l edge may be formed in any suitable way other than that herein explained.

\Vhat is claimed is- 1. The process of makinghollow metal balls consisting in forming a metallic cup with a laterally-inclined irregular edge, and then closing the open end of the cup to form a sphere.

2. The process of makinghollow metal balls consisting in forming a metallic cup with a laterally and inwardly inclined irregular edge,

and then closing the open end of the cup to form a sphere.

3. The process of making hollow metal balls consisting in forming a metallic cup with a pointed edge laterally and inwardly inclined, and then closing the cup to form a sphere.

4. The process of makinghollow metal balls consisting in forming from a sheet-metal blank a cup with a laterally and inwardly inclined irregular edge, and then closing the cup to form a sphere.

5. The process of making metallic balls consisting in forming from a square sheet-metal blank a cup with a pointed and laterally and inwardly inclined edge, and then closing the cup to form a sphere.

6. The process of making hollow metal balls consisting in drawing a sheet-metal blank into a cup having its outer surface extending beyond its inner surface thereby forming a laterally-inclined irregular edge, and then closing the cup to form a sphere.

7. The process of making hollow metal balls consisting in drawing a sheet-metal blank into the form of a cup having an inwardly-inclined irregular edge and the side wall of which is thinner than the original thickness of the blank, and then closing the cup to form a sphere.

8. The process of making hollow metal balls consisting in drawing a sheet-metal blank of suitable shape into a cup having a laterally and inwardly inclined irregular edge by means of a punch and die having a difference of diameter less than twice the original thickness of the blank, and then closing the cup by bringing said inclined edge together to form a closed seam.

9. The process of makinghollow metal balls consisting in simultaneously forming a metallic cup with an irregular edge and imparting a lateral inclination to said edge, and then closing the open end of the cup to form a sphere.

10. The process of making hollow metal balls consisting in simultaneously forming a metallic cup with an irregular edge from a sheet-metal blank and imparting a lateral inward inclination to said edge, and then closing the open end of the cup to form a sphere.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

ALLEN JOHNSTON. Witnesses:

FRANK BEACH, LEO E. STEVENS. 

